人为不同干扰条件下荒漠啮齿动物群落格局的动态特征--动物与植物群落的典型相关分析

Desert rodent communities patterns under different disturbances:the canonical correlation analysis of rodent and plant communities

群落的格局和动态是群落生态学和生态系统生态学研究中的基础问题,也是揭示群落结构和功能的核心问题。为了深入了解生态系统的结构与功能,研究啮齿动物群落格局在人为不同干扰下的动态特征,特别是研究荒漠区的脆弱生态系统中啮齿动物群落格局在人为不同干扰下的动态特征,是揭示人为干扰下荒漠生态系统结构和功能变化特征的基础。2002～2004年在内蒙古阿拉善典型荒漠区,选择了4种不同干扰条件的生境,分别为禁牧区、过牧区、轮牧区和开垦区,研究了人为不同干扰下啮齿动物群落格局的变动趋势,应用典型相关方法分析了啮齿动物群落与植物群落在不同干扰条件下的相互关系。结果表明,在两种观察尺度域上(标志样地和线路样地)动物群落变量与植物群落变量的相关关系表现为:动物群落变量与植物群落变量中的草本关系最为突出,在分析的两个尺度的8个样地中,除标志样地的过牧区外,其它7个样地均与草本关系密切,且绝大多数样地动物群落变量与草本的盖度和地上生物量呈负相关关系。这说明荒漠生态系统中,在4种干扰条件下,草本的特性,特别是草本的盖度和地上生物量对啮齿动物群落格局及其动态变化起到关键作用,其值越大,啮齿动物群落组成种的丰富度(数量)和生物量就越小。就同一种干扰条件下的两种尺度域上的情况看,动物群落和植物群落的相关性较突出的特点是:在禁牧区和开垦区,喜湿的种类(黑线仓鼠和草原黄鼠)与植被的相关性显著,在轮牧区和过牧区,喜旱的种类(小毛足鼠和三趾跳鼠)与植被的相关性显著,且均与草本呈负相关关系。

Four site types, under different kinds of disturbed habitats, were selected in the typical region of the Alashan Desert of Inner Mongolia; this selection dates back from April to October 2002, 2003 and 2004 respectively, i.e. a farmland area, a rotational-grazing area, a over-grazing area and a prohibited-grazing area. The rodent communities＇ fluctuating tendency was studied by using mark-recapture and trap-day methods. The four kinds of mark-recapture sites and that of line sites were taken in different disturbance areas. The area of the mark-recapturing site was 0.95 hm^2 and the line site 10 km^2. The samples were collected every month in the mark-recapturing sites for 4 consecutive days and in line sites in April, July, and October every year. The variable matrix was composed of captured numbers of the rodent communities. The relationship between rodent communities and plant ones was analyzed with Canonical Correlation Analysis （CCA） under different disturbances. The results shows that the relation between the rodent communities variables and herbage ones of plant communities is significant, on two scales in three years, under different disturbances excepting over-grazing area of marking sites, where 7 of the 8 sites analyzed are closer with herbage in two scales. The relation between the rodent community＇s variables and the coverage, biomass above ground of herbage ones is negative. This shows that the coverage and biomass above ground of herbage took a key effect to pattern and dynamics of rodent communities under 4 different disturbances in desert ecosystem. The coverage values and biomass above ground of herbage are higher, and those of richness and biomass of rodent communities composition species are lower. Under the same disturbance, on two scales, the main characteristic of mutuality between rodent communities and plants is as follows： In farmland and prohibited areas, the mutuality between hydrophilic species （Cricetulus barabensis and Spermophilus dauricus ） and vegetation is significant. In rotational-grazing and overgrazing areas, the mutuality between xerophilic species （Dipus sagitta and Phodopus roborovskii） and vegetation is very indicative. And above mutuality between animal species and herbage of vegetation is negative.